1. Field of the Invention
The present invention generally relates to a window assembly. More specifically, the present invention relates to a window assembly including a primer and an encapsulation.
2. Description of the Related Art
Primers for bonding an encapsulation are generally known in the art. Generally, window assemblies include a transparent pane, commonly made from glass. A ceramic frit is disposed about a perimeter of the transparent pane by methods commonly known in the art, like printing the ceramic frit on the transparent pane. The encapsulation is bonded to the perimeter of the transparent pane. The encapsulation can be bonded to one, two, or three surfaces of the transparent pane. Generally, the encapsulation can be either a thermoset material, such as a reaction injection molded (RIM) material, or a thermoplastic material, such as polyvinylchloride (PVC) or a thermoplastic elastomer (TPE) material.
The encapsulation is bonded to the transparent pane via the primer. Said differently, the encapsulation bonds to the primer, which is bonded to the transparent pane, thereby bonding the encapsulation to the transparent pane. The primer increases a bond strength between the encapsulation and the transparent pane as compared to a bond strength between the encapsulation and the transparent pane without the primer. Said differently, the encapsulation bonds better to the primer than it does with the transparent pane directly. The primer also serves to conceal an exposed edge of the transparent pane, which provides a more aesthetically pleasing appearance.
The ceramic frit has a color, which is typically referred to as black, for absorbing solar energy and impeding the solar energy from penetrating the window assembly. Preventing the solar energy from penetrating the window assembly prevents degradation of chemical and physical properties of the primer, thereby preserving the bond strength between the encapsulation and the transparent pane. When the encapsulation is bonded to three surfaces of the transparent pane, known in the art as a three-sided encapsulation, the ceramic frit and the primer are substantially covered and the color of the primer is not important. However, when the encapsulation is only bonded to one or two surfaces of the transparent pane, known in the art as one-sided or two-sided encapsulations, respectively, the primer is visible from the exterior of the vehicle. In such a case, it is desirable for a color of the primer to blend with the color of the ceramic frit so that an observer is not able to differentiate between the ceramic frit and the primer thereby providing an aesthetically pleasing appearance of the window assembly.
The primer is selected from known conventional primers based on the material used to make the encapsulation. For example, the conventional primers used with the thermoset material chemically react with the thermoset material of the encapsulation to chemically bond the encapsulation to the primer. More specifically, the conventional primers used for the thermoset material of the encapsulation are polyurethane primers, which are isocyanate-based, and react with the thermoset material to form covalent bonds. The conventional primers used for the thermoset material are short chain polymers due to the chemical bond that is to be formed. Alternatively, the conventional primers used with the thermoplastic material provide an adhesive bond and do not chemically react with the thermoplastic material of the encapsulation. More specifically, the conventional primers used with the thermoplastic material are typically long chain polymers that only mix with the thermoplastic material, which results in polymer chain entanglement. Generally, the conventional primers used with the thermoset material cannot be used with thermoplastic material because the conventional primers used with the thermoset material are short chain polymers, which are inadequate for mixing with the thermoplastic material.
The conventional primers used when the encapsulation is the thermoset material have a color that is referred to as black and generally blend with the color of the ceramic frit, which is desirable. However, using the thermoset material for the encapsulation is more costly than using the thermoplastic material. The thermoplastic material rather than the thermoset material for the encapsulation may be used to reduce manufacturing costs of the window assemblies.
The conventional primers available for use when the encapsulation is the thermoplastic material are typically transparent or differently colored from the black color of the ceramic frit. For example, when the encapsulation is PVC, the primer is typically a transparent light green color. As described above, the conventional primers used with the thermoset material cannot be used with the thermoplastic material. Therefore, when the encapsulation is the thermoplastic material, the window assembly cannot benefit from the black color of the conventional primers used when the encapsulation is the thermoset material and must use either the transparent conventional primers or the differently colored conventional primers.
The transparent conventional primers use with the thermoplastic material are not desirable because the exposed edge of the transparent pane remains visible or is even accentuated, which results in a poor aesthetic appearance. Additionally, the differently colored conventional primers used with the thermoplastic material do not blend with the black color of the ceramic frit, which results in a poor aesthetic appearance. Therefore, cost savings associated with manufacturing the window assemblies using the thermoplastic material rather than the thermoset material cannot be realized without sacrificing the aesthetic appearance of the window assemblies.